ISO 19136-1:2020

Overview

ISO 19136-1:2020 - Geographic information - Geography Markup Language (GML) - Part 1: Fundamentals defines the fundamentals of GML (Geography Markup Language) as an XML encoding (in accordance with ISO 19118) for the transport and storage of geographic information. The standard provides the XML Schema syntax, mechanisms and conventions to describe geospatial application schemas that include both spatial and non‑spatial properties of geographic features. It establishes an open, vendor‑neutral framework to enable sharing, profiling and linking of geographic application schemas and datasets.

Key technical topics and requirements

• XML Schema syntax and conventions: normative rules for defining GML application schemas in XML Schema (XSD).
• GML framework and profiles: mechanisms to define profiles that support proper subsets of GML capabilities for constrained or domain‑specific use.
• Conformance classes: specified conformance requirements for application schemas, profiles, documents and software implementations.
• Base schema components (gmlBase): common objects, properties, collections and metadata elements used across GML application schemas.
• Object associations and XLinks: remote properties and linking mechanisms for distributed datasets.
• Basic types and lexical conventions: scalar types, lists and relationships with ISO 19103.
• Feature and geometry modelling: definition of Feature types, standard feature properties (e.g., boundedBy), geometry primitives (0D–3D), curves, surfaces, solids, complexes and aggregates.
• Spatial reference and coordinate geometry: rules for specifying spatial reference systems and coordinate encoding used in features and collections.
• Temporal and topology properties: support for temporal extents and topological relationships.
• Versioning and deprecated components: conventions for namespace versioning and handling deprecated elements.
• Mapping from UML application schemas: normative mapping rules from ISO 19109‑conformant UML application schemas to GML XML Schema.

Practical applications and who uses it

ISO 19136-1:2020 is used by:

• GIS software vendors and developers implementing GML encoding, XML Schema validation and data interchange.
• Data providers and national mapping agencies publishing standardized datasets for sharing and archival.
• System integrators and IT teams converting proprietary geospatial formats to/from a vendor‑neutral XML encoding.
• Standards bodies and domain communities creating specialized geospatial application schemas and profiles.

Typical uses include encoding and exchanging feature datasets (points, lines, polygons, 3D solids), transporting application schemas between organizations, enabling linked geographic schemas and ensuring interoperable storage/transport for geospatial information.

Related standards

• ISO 19118 (XML encoding rules) - referenced for encoding conformity.
• ISO 19109 (Rules for application schema) - provides UML‑based application schema rules and mapping guidance used normatively by ISO 19136‑1.

ISO 19136-1:2020 is essential for organizations needing a standards‑based, interoperable XML framework for geospatial data exchange, schema definition and long‑term storage.